A Study on the Use of Construction Wastes as Coarse Aggregates on High Performance Concrete
In recent years, because of rising consciousness on environmental protection and the lacking of construction waste dumping yards, recycling of construction wastes has been promoted extensively. The purpose of this study is to ascertain the effect on properties of the fresh and harden concrete replacing coarse aggregates by construction wastes under ambient and enhanced temperatures exposure. This research mainly concentrates on high performance recycled concrete (HPRC); by adding different amount of superplasticizer into the HPRC and to test and compare its mechanical and thermal properties with general high performance concrete (HPC). Thereafter, tests are carried out determine its compressive strength, residual strength after high temperature and the loss on ignition of the HPRC mixed with two water-to-cement ratios and different replacement proportions of recycled aggregates. Similar tests, such as the slump test and slump flow test, are carried out both on the HPRC and HPC. When the water-to-cement ratio is 0.3 and the amount of superplasticizer added is 1.2%, HPRC has the best performance. The specimens with 100% recycled aggregates were 31% below the control concrete sample in compressive strength at age of 28 days. By the way of adding admixture, the recycled concrete could reach the demand strength of the HPC. The results show that it is feasible to allow a higher replacement percentage of construction wastes for producing concrete products.
C. M. Ho and W. T. Tsai, "A Study on the Use of Construction Wastes as Coarse Aggregates on High Performance Concrete", Advanced Materials Research, Vols. 163-167, pp. 1525-1531, 2011